A method to reproduce by rotary magnetic heads a magnetic tape of slant-recorded video tracks to thereby obtain a still picture, has been proposed by the U.S. Pat. No. 3,943,562. The patent relates to positional control of a tape, i.e., control of a tape transport motor, for reproducing a still picture. The present invention, which employs video heads of mutually different azimuth angles and a recording tape of the so-called guard-band-less type, is different from the above Patent in a form of an envelope of reproduced signal by the video heads, whereby the motor control system also differs from the Patent. The motor control system has been proposed by the U.S. Pat. Nos. 3,789,138 and 3,968,518, both the patents relating to a method by which the tape is brought to a halt at a required position. While, the present invention produces from the reference signal two kinds of signals for driving the tape transport motor during reproducing a still and a slow motion picture, the two signals being properly combined to obtain a smooth slow-motion reproduction and a noiseless signal on the television picture. Therefore, both the above patents differ from the present invention.